Hydraulic braking system



HYDRAULIC BRAKING SYSTEM Fledv May 1. 1936 2 Sheets-Sheet l 6am wel! In venior A flor ne y tributing cylinder, between the two oating pistons. When the brake pedal is depressed to apply the brakes, the fluid pressure at the central part of the distributing chamber separates the two floating pistons, pushing them outwardly against their return springs 20 and 2l against the two cylinder heads 22 and 23, and the oil in the end portions of the distributing cylinder is thus placed under pressure. It will be understood, of course, that, in addition to the supply of oil at the central part of the distributing cylinder between the floating pistons, the two ends of the distributing cylinder and the brake pipes l2, i4 and? brake cylinders i3, i5 are also filled with oil. Thus the pressure of the master-cylinder-oil is extended through the floating pistons to the auxiliary supply of oil in the ends of the distributing cylinder,

the brake or oil pipes, and the brake cylinders, and the brakes are applied in usual manner. When the depressed brake pedal is released, the spring S returns the main piston, and the springs 2d and 2i return the floating pistons to normal pressure position, and the brakes are released.

Should the brake pressure, as distinguished from the master-cylinder-pressure or pedal-pres sure, be reduced, (as by a leak and loss of oil with consequent loss of brake pressure) the greater pedal pressure is instrumental in' putting out di commission the enacted fioating piston that would otherwise supply the brake-pre4ure For ren'- dering inoperative either or both oi the floating, operating pistons, I provide' each head 22 and 22 oi the distributing cylinder with a spring catch 26 comprising twin spring hooks iixed to the inner faces of the heads, and the outer face of each of the operating or floating pistons is provided with a central pin 2l having a hook or catch 2l.

Thus, should an oil leak occur in an oil or .brake pipe, and the brake pedal thereafter be depressed, the pedal-pressure will push the corresponding operating piston, against the reduced brake-pressure, until the hook or head 26 engages the spring catch 24, and the iloating piston is then held staf tionary at the end of the distributing cylinder. Through the compensating port, the master cylinder is furnished with additional oil to flll the void created by the displacement of the noating piston, and the pedal pressure is thus maintained in the distributing cylinder. The brake-pressure of the unaffected pipeline is not disturbed nor changed, and therefore, as here illustrated, the brakes of two of the wheels will be operated as long as the pedal is operated.-

For releasing the spring latch and thusfreeing the affected floating piston, I provide a release bolt 21 in each of' the distributing cylinder-heads, which bolts project into the interior of the cylalcala-i inder between the spring hooks 24 of the latches. These release bolts are provided with an exterior wrench-.head 28 and at their inner ends they are each fashioned with a pair of cams 29. When the release bolt is turned by the use vof a wrench, the cams spread apart the twin hooks 24, thereby releasing the hook or head 28.

After a leak has been stopped or plugged, the oil supplyA for the affected brake-line pressure is again replenished, from the reservoir and master cylinder, through a port 30 of the distributing cylinder, which leads into a duct 3|- extending longitudinally in the wall of the cylinder with endports opening into the opposite ends of the cylinder beyond therange of movement of the two iniiating or operating pistons. At each side of the port 30 the duct 3i is provided with a threeway valve as 22 and .32, each of which is secured in closed position by means of a set bolt as 34. It the leak has occurred at the right of the piston it, for instance, in Figure 5, the valve 32 is turned to afford communication through duct 3| from the port 30, and the required quantity of oil is thus supplied to the distributing cylinder at the right side of valve 22 and into the right end of the distributing cylinder, and of course the replenished oil supply extends through the brake lpipe tothe brake cylinder. By use of the threeway valve, when opened, air may/,be vented from the distributing cylinder thus permitting and insuring a full supply of oil from the reservoir 2 through the master cylinder and to the braking system.

Iniilgure 3a the use of an additional distributing'cyllmler 25 is indicated, when the braking sys tem is extended to the wheels of a trailer, for instance. This secondary distributing cylinder receives fluid pressure from one of the main pipes,

as i4, and thence by pipes 3l and 21 the pressure is transferred to the trailer brakes.

Having thus fully described my invention, what I claim as new and desire to secure by letters Patent isz- A In a hydraulic braking system) the combination of a distributing cylinder having removable heads and brake-pressure pipes connected thereto, a pair of spaced floating pistons having abutting -bosses to provide a central space, an inlet port and an outlet port communicating with said space, said outlet port communicating with a duct in a longitudinal wall of the cylinder and said duct having ports opening into the cylinder adjacent its opposite ends, and a three-way valve in said duct at each side of said outlet port for controlling passage of pressure-fluid therethrough. l

LEROY CORNWELL. 

